Narendra Modi, Chief Minister of India's western Indian state of Gujarat and main opposition Bharatiya Janata Party (BJP) leader, addresses his party supporters at an election campaign rally in the northern Indian city of Allahabad April 12, 2009.

On Thursday, Dec. 20, as results come in from this week’s elections in Gujarat, Indians will learn the outcome of a state poll that has taken on the flavor of a national referendum. If, as widely expected, Chief Minister Narendra Modi cruises to a third successive victory, he will cement his position as India’s leading opposition politician and its top contender to succeed Prime Minister Manmohan Singh after national elections that will come no later than the middle of 2014. By contrast, an unlikely defeat, or even a narrow victory, will set back the controversial leader’s national ambitions.

Love him or hate him, there’s no denying that 62-year-old Modi is India’s most polarizing politician. For his legion of supporters — including many of his 1.1 million followers on Twitter — Modi is the messiah who will rid Indian politics of sloth, corruption, and petty identity politics. With his no-nonsense management style and inspirational leadership, only he can deliver the economic development Indians crave, say his fans. For his equally vocal detractors, Modi is forever tarred by anti-Muslim riots that occurred 10 years ago, early in his first term as chief minister. Enraged by the burning alive of a group of Hindu pilgrims on a train, mobs went on a three-day rampage that killed about 1,000 people, nearly four-fifths of them Muslim. To Modi’s critics, he represents a dangerous Hindu majoritarianism that threatens India’s tradition of pluralism and tolerance toward all faiths. They also pooh-pooh his economic management as hype, the product of good fortune and a well-oiled public relations machine.

No matter which argument you prefer, the heightened passions Modi evokes have elevated the Gujarat election — voting was held in two phases on Dec. 13 and 17 — to a status way above just another provincial poll in one of India’s 28 states. On the outcome hinges the immediate future of India’s main opposition party, the Hindu-nationalist Bharatiya Janata Party (BJP), which rules 10 states alone or with partners and commands about one-fifth of the national vote. (The ruling Congress party draws between 25 and 30 percent in national elections.) And with the possibility looming that an enfeebled and scandal-plagued Singh government won’t serve out its full term — the ruling coalition lost its parliamentary majority with a key partner’s exit in September — the long-standing question of Modi’s national prospects also acquires a new salience.

Simply put, those clamoring for Modi’s elevation as the BJP’s candidate to lead India underestimate the downsides for the party and the country. Despite his reputation as the country’s best economic administrator and most business-friendly politician, Modi’s association with anti-Muslim sentiment makes him ill-suited to lead his party’s evolution toward a moderate Indian conservatism, a right-of-center alternative to the left-of-center Congress. Nor is it clear that Modi’s top-down management style — perfected in a state where he holds unquestioned sway — will work in India’s fractured national polity. And finally, given India’s tough neighborhood and growing international engagement, the last thing the country needs is a leader who diminishes one of its greatest assets — a well-deserved reputation for pluralism.

The best way to understand the Modi phenomenon is to view him through the prism of his supporters. For them, the chief minister is that rarest of creatures in India: a politician more interested in public service than in pelf or promoting his progeny.

Indeed, an idealized view of Modi consists of a series of contrasts. In a land swaddled with red tape, Modi is seen as a go-getter. In a culture of inherited privilege — where politicians tend to hand down power to their children like a family heirloom — the chief minister comes from humble stock and has risen through dint of effort. He began his career helping an uncle run a railway-station tea stall in his hometown and then worked his way up the ranks of the Hindu-nationalist group Rashtriya Swayamsevak Sangh (National Volunteer Corps) and its sister organization, the BJP, before being catapulted to the chief minister’s job in 2001.

In an era of staggering corruption, Modi also stands for personal austerity. He’s one of India’s few politicians — Singh is another — whose declaration of a meager net worth (about $245,000) doesn’t evoke guffaws of disbelief. So widely held is the idea of Modi as a paragon of probity that the national media mostly ignored anti-corruption activist Arvind Kejriwal’s allegations this month that the Modi government gave sweetheart gas, land, and power deals to businesses considered close to the chief minister.

For Modi’s supporters, these qualities — decisiveness and honesty — set him apart from most politicians and from the Nehru-Gandhi dynasty that has dominated Indian public life since independence from Britain in 1947. Here’s proof that good governance can emerge from the murk of Indian politics. Here is an earthy and effective alternative to Congress President Sonia Gandhi’s to-the-manor-born 42-year-old son, Rahul, widely seen as his party’s prime minister in waiting. As a bachelor, Modi carries no burden of sticky-fingered children, or their corner-cutting spouses, out to make a quick buck from proximity to power.

Biography notwithstanding, the heart of Modi’s claim to higher office lies in the so-called Gujarat miracle. The state has averaged double-digit growth rates over much of Modi’s 11-year rule. With only 5 percent of India’s population, last year Gujarat accounted for 16 percent of the country’s manufacturing and 22 percent of its exports. The Economist calls it India’s Guangdong.

While it’s impossible to quantify Modi’s contribution to his state’s economic performance, over the years he has earned a reputation for problem-solving. While much of India continues to suffer from potholed roads and daily brownouts, Gujarat offers investors modern highways and a reliable power supply. Many of India’s tycoons have lavished praise on Modi for running an administration responsive to their needs. In 2008, Modi famously persuaded Ratan Tata to build the Nano, the world’s cheapest car, in Gujarat after Tata Motors ran into land-acquisition troubles in West Bengal. Every two years, Indian and global businesses line up at the Vibrant Gujarat summit to pledge billions of dollars to the state in India’s most high-profile investor gathering. Foreign companies that have set up shop in Gujarat under Modi, or announced plans to do so, include Abbott, Bombardier, Ford, Peugeot, and Suzuki.

Ten years of peace and a booming economy have gained Modi a measure of international acceptance outside business circles as well. A spate of essays and articles in the international press this year has focused on Modi the manager rather than on the riots. In October, Britain ended its post-riots boycott of Gujarat by sending its high commissioner in New Delhi to confer with Modi. However, the United States, which denied Modi a visa in 2005, has yet to follow suit.

For the most part, nationwide political polling in India is as much crapshoot as science, and Modi’s popularity with voters has never truly been tested outside Gujarat. Nonetheless, a smattering of evidence suggests a strong following among the pan-Indian middle class and the Indian diaspora. A poll by India Today this year declared Modi the country’s top pick for prime minister: 24 percent of respondents chose him, compared to 17 percent who preferred Rahul Gandhi. If you criticize Modi on the Internet, you’re sure to encounter what Business Standard’s Mihir Sharma calls the chief minister’s “army of crazed amateur defenders.” Traffic at a Google Plus “hangout” featuring Modi in August reportedly crashed the website’s servers. Many of Modi’s most fervent supporters are hypernationalists who seem to view opposition to him as unpatriotic.

However, the passion Modi evokes runs both ways. This year, for instance, he garnered the third-most votes worldwide in Time magazine’s annual poll to help choose the “100 most influential people” in the world. But though 256,828 people plumped for Modi — about 10 times the number who picked U.S. President Barack Obama — even more (266,739 people) gave the chief minister a thumbs-down.

If Modi’s supporters view him through the prism of development, his critics define him by the 2002 violence. For them there’s no statute of limitations on India’s worst riots in a generation. Modi’s critics accuse him of abetting the violence by telling the police to turn a blind eye, or at best failing to control the rampaging mobs. They also accuse him of lacking remorse by steadfastly refusing to apologize for the barbarism that occurred on his watch. For his part, Modi stoutly denies any wrongdoing and says he should be hanged if found guilty. In April, an investigation ordered by the Supreme Court cleared him of culpability for the riots, but its findings are subject to appeal. Regardless of the final outcome, the taint of 2002 makes Modi toxic for the one-in-eight Indians who are Muslim, and for many liberal-minded Hindus as well.

For skeptics, Modi’s vaunted economic record also needs to be taken with a pinch of salt. As the argument goes, Gujaratis have always been an entrepreneurial people — in the United States they dominate the motel industry — and would likely have prospered even without Modi. Moreover, while Gujarat has grown fast, other states have grown faster still, and the state’s human development indicators are not nearly as impressive as its GDP figures.

On balance, though, the economic argument against Modi appears weak. Most states that have grown faster than Gujarat either are much smaller or are starting from a much lower base. Moreover, human development indicators often lag income gains, and the effects of sustained double-digit growth in Gujarat will likely become evident over the coming years. In a new book, India’s Tryst With Destiny, Columbia University economists Jagdish Bhagwati and Arvind Panagariya credit Gujarat with making greater strides in health and education since independence than Kerala, which is often held up as India’s poster child in terms of human development.

Moreover, there’s more to Modi’s economic message than GDP growth alone. No other Indian chief minister stands up publicly for the idea of small government, fiscal responsibility, getting the government out of business, and providing people jobs rather than handouts.

But giving Modi his due as an administrator is not the same as endorsing him to lead either his party or the country. For the BJP, the most pressing challenge is to transform itself into a modern conservative party that appeals to Indians of all faiths, as well as to liberal-minded Hindus who believe that India could do with a dose of fiscal rectitude and a more muscular approach to national security. Picking a moderate figure such as the urbane former law minister Arun Jaitley to lead the party would send exactly this message. Modi may well energize the BJP’s base, but thanks to the shadow of the 2002 riots, he will likely also repel religious minorities and narrow the number of allies willing to partner with the BJP in a coalition.

For India more broadly, it makes no sense to elect a leader associated with a chapter of history the country would rather forget. In late November, 25 members of the U.S. Congress sent a letter to Secretary of State Hillary Clinton urging her to continue to deny Modi a U.S. visa. On the world stage, a Modi-led India would need to expend too much energy defending its commitment to secular democracy rather than pursuing pressing economic and strategic objectives. In the immediate neighborhood, ties with Muslim-majority Bangladesh and Pakistan would take a beating. Farther afield, India’s soft power would lose some of its appeal.

What then for the talented Mr. Modi? Oddly enough, his may be a case where Indian democracy is actually working. Ever since the riots, India has effectively placed Modi on a hamster wheel of permanent penance, forcing him to try to rehabilitate himself through good governance. Perhaps this place — serving as an electorally successful, economically savvy chief minister who can inspire others — is where he belongs. Alternatively, should the BJP recapture power in New Delhi, appointing Modi as an economic czar, perhaps as both finance and trade minister, would send the right message to domestic and foreign investors alike.

In short, Narendra Modi may well be India’s best chief minister. But he’d still make a terrible choice for prime minister.